The present invention concerns measurement devices and more particularly a device providing convenient measurement and numeric display of a volume dependent characteristic of any selected part of an item such as a fish fillet.
Such devices are described and claimed in U.S. Pat. Nos. 7,158,915 and 7,010,457 issued to the present inventor, both of which patents are hereby incorporated by reference herein.
In those patents, a device is described which includes a hand held elongated sensor member constrained to be spaced above a table surface at a fixed height by the presence of support structure such as a post extending down from each end of the sensor member. Both posts are held in contact with the table surface during stroking of the sensor member over the item so that the sensor member is positioned above the table surface at a fixed height which is sufficiently high to insure that the sensor member is able to be passed over an item lying on the table surface.
A displacement detector arrangement generates signals corresponding to the extent and direction of movement of the sensor member along the item. At the same time a sensor arrangement on the sensor member generates signals corresponding to the cross sectional contour of the item at each of its successive sections passed over by the sensor member as it is stroked along the item. Both the detector and sensor signals are processed by a signal processor to electronically calculate the volume of segments of the item passed over by the sensor member and a corresponding numeric value is displayed such as the price or weight of any segment of the item passed over by the sensor member.
As noted, the length of the posts positively determines the height at which the sensor member is spaced above the table while being passed over the item.
The sensor member support structure in most embodiments described in the above referenced patents comprises the two support posts, each projecting down from a respective end of the sensor member. A gantry support structure for the sensor member is also described in U.S. Pat. No. 7,158,915 which likewise maintains the sensor member at a predetermined fixed height above the table surface during movements of the sensor member over the item. Guiding the sensor member to pass over the item at a predetermined fixed height above the table and item has some disadvantages.
Since the support structure prevents the sensor member from moving down to be closer to the item it may be necessary to provide an ability to vary the dimensions of the support structure to accommodate thicknesses of the item greater than the height at which it is supported by the support structure, and this could be done with adjustable or replaceable sets of posts or adjustable gantry structure but this solution would add complexity and cost to the device.
The presence of the posts or other support structure also makes it impossible to use a knife blade on the sensor member to cut or score the item since the presence of the support structure would interfere with any attempt to bring the knife blade down to cut or mark the item.
The above referenced U.S. Pat. No. 7,158,915 to the present inventor also describes retractable posts to allow effective use of a cutting blade mounted on the sensor member, but this retractable post arrangement would also add complexity and cost to the device. Also, since the posts are held in contact with the table surface, and that surface could be greasy, dirty, marred, etc., this could create difficulties and inaccuracies in measurement.
It is an object of the present invention to provide an apparatus of the type described in which the sensor member does not have to have any portions in contact with the table surface and is freely movable to allow manual positioning and stroking of the sensor member at any height above the table surface and item and also to contact the item with a knife blade on the sensor member while still providing an accurate measurement of the volume of any segment of the item if the height of the sensor member is varied while being passed over the item.